Active Stylus with Energy Harvesting

ABSTRACT

In one embodiment, a stylus includes one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for transmitting signals wirelessly from the stylus to a device through a touch sensor of the device. The stylus has one or more sensors for kinetic, thermal, solar or electric energy harvesting from an environment of the stylus or from the stylus itself.

RELATED APPLICATION

This application claims the benefit, under 35 U.S.C. §119(e), of U.S.Provisional Patent Application No. 61/553,114, filed 28 Oct. 2011, whichis incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to active styluses.

BACKGROUND

A touch sensor may detect the presence and location of a touch or theproximity of an object (such as a user's finger or a stylus) within atouch-sensitive area of the touch sensor overlaid on a display screen,for example. In a touch-sensitive-display application, the touch sensormay enable a user to interact directly with what is displayed on thescreen, rather than indirectly with a mouse or touch pad. A touch sensormay be attached to or provided as part of a desktop computer, laptopcomputer, tablet computer, personal digital assistant (PDA), smartphone,satellite navigation device, portable media player, portable gameconsole, kiosk computer, point-of-sale device, or other suitable device.A control panel on a household or other appliance may include a touchsensor.

There are a number of different types of touch sensors, such as, forexample, resistive touch screens, surface acoustic wave touch screens,and capacitive touch screens. Herein, reference to a touch sensor mayencompass a touch screen, and vice versa, where appropriate. When anobject touches or comes within proximity of the surface of thecapacitive touch screen, a change in capacitance may occur within thetouch screen at the location of the touch or proximity. A touch-sensorcontroller may process the change in capacitance to determine itsposition on the touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor with a touch-sensorcontroller.

FIG. 2 illustrates an example active stylus exterior.

FIG. 3 illustrates an example active stylus interior.

FIG. 4 illustrates an example active stylus with touch sensor device.

FIG. 5 illustrates example power management systems and power sourcesfor a touch sensor system.

FIG. 6 illustrates an example active stylus with kinetic energyharvesters.

FIG. 7 illustrates an example active stylus with thermal energyharvesters.

FIG. 8 illustrates an example active stylus with electric energyharvesters.

FIG. 9 illustrates an example active stylus with solar energyharvesters.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates an example touch sensor 10 with an exampletouch-sensor controller 12. Touch sensor 10 and touch-sensor controller12 may detect the presence and location of a touch or the proximity ofan object within a touch-sensitive area of touch sensor 10. Herein,reference to a touch sensor may encompass both the touch sensor and itstouch-sensor controller, where appropriate. Similarly, reference to atouch-sensor controller may encompass both the touch-sensor controllerand its touch sensor, where appropriate. Touch sensor 10 may include oneor more touch-sensitive areas, where appropriate. Touch sensor 10 mayinclude an array of drive and sense electrodes (or an array ofelectrodes of a single type) disposed on one or more substrates, whichmay be made of a dielectric material. Herein, reference to a touchsensor may encompass both the electrodes of the touch sensor and thesubstrate(s) that they are disposed on, where appropriate.Alternatively, where appropriate, reference to a touch sensor mayencompass the electrodes of the touch sensor, but not the substrate(s)that they are disposed on.

An electrode (whether a ground electrode, guard electrode, driveelectrode, or sense electrode) may be an area of conductive materialforming a shape, such as for example a disc, square, rectangle, thinline, other suitable shape, or suitable combination of these. One ormore cuts in one or more layers of conductive material may (at least inpart) create the shape of an electrode, and the area of the shape may(at least in part) be bounded by those cuts. In particular embodiments,the conductive material of an electrode may occupy approximately 100% ofthe area of its shape. As an example and not by way of limitation, anelectrode may be made of indium tin oxide (ITO) and the ITO of theelectrode may occupy approximately 100% of the area of its shape(sometimes referred to as a 100% fill), where appropriate. In particularembodiments, the conductive material of an electrode may occupysubstantially less than 100% of the area of its shape. As an example andnot by way of limitation, an electrode may be made of fine lines ofmetal or other conductive material (FLM), such as for example copper,silver, or a copper- or silver-based material, and the fine lines ofconductive material may occupy approximately 5% of the area of its shapein a hatched, mesh, or other suitable pattern. Herein, reference to FLMencompasses such material, where appropriate. Although this disclosuredescribes or illustrates particular electrodes made of particularconductive material forming particular shapes with particular fillpercentages having particular patterns, this disclosure contemplates anysuitable electrodes made of any suitable conductive material forming anysuitable shapes with any suitable fill percentages having any suitablepatterns.

Where appropriate, the shapes of the electrodes (or other elements) of atouch sensor may constitute in whole or in part one or moremacro-features of the touch sensor. One or more characteristics of theimplementation of those shapes (such as, for example, the conductivematerials, fills, or patterns within the shapes) may constitute in wholeor in part one or more micro-features of the touch sensor. One or moremacro-features of a touch sensor may determine one or morecharacteristics of its functionality, and one or more micro-features ofthe touch sensor may determine one or more optical features of the touchsensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates)and the conductive material forming the drive or sense electrodes oftouch sensor 10. As an example and not by way of limitation, themechanical stack may include a first layer of optically clear adhesive(OCA) beneath a cover panel. The cover panel may be clear and made of aresilient material suitable for repeated touching, such as for exampleglass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA may be disposed between the cover paneland the substrate with the conductive material forming the drive orsense electrodes. The mechanical stack may also include a second layerof OCA and a dielectric layer (which may be made of PET or anothersuitable material, similar to the substrate with the conductive materialforming the drive or sense electrodes). As an alternative, whereappropriate, a thin coating of a dielectric material may be appliedinstead of the second layer of OCA and the dielectric layer. The secondlayer of OCA may be disposed between the substrate with the conductivematerial making up the drive or sense electrodes and the dielectriclayer, and the dielectric layer may be disposed between the second layerof OCA and an air gap to a display of a device including touch sensor 10and touch-sensor controller 12. As an example only and not by way oflimitation, the cover panel may have a thickness of approximately 1 mm;the first layer of OCA may have a thickness of approximately 0.05 mm;the substrate with the conductive material forming the drive or senseelectrodes may have a thickness of approximately 0.05 mm; the secondlayer of OCA may have a thickness of approximately 0.05 mm; and thedielectric layer may have a thickness of approximately 0.05 mm. Althoughthis disclosure describes a particular mechanical stack with aparticular number of particular layers made of particular materials andhaving particular thicknesses, this disclosure contemplates any suitablemechanical stack with any suitable number of any suitable layers made ofany suitable materials and having any suitable thicknesses. As anexample and not by way of limitation, in particular embodiments, a layerof adhesive or dielectric may replace the dielectric layer, second layerof OCA, and air gap described above, with there being no air gap to thedisplay.

One or more portions of the substrate of touch sensor 10 may be made ofpolyethylene terephthalate (PET) or another suitable material. Thisdisclosure contemplates any suitable substrate with any suitableportions made of any suitable material. In particular embodiments, thedrive or sense electrodes in touch sensor 10 may be made of ITO in wholeor in part. In particular embodiments, the drive or sense electrodes intouch sensor 10 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, one or moreportions of the conductive material may be copper or copper-based andhave a thickness of approximately 5 μm or less and a width ofapproximately 10 μm or less. As another example, one or more portions ofthe conductive material may be silver or silver-based and similarly havea thickness of approximately 5 μm or less and a width of approximately10 μm or less. This disclosure contemplates any suitable electrodes madeof any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 may include an arrayof drive and sense electrodes forming an array of capacitive nodes. Adrive electrode and a sense electrode may form a capacitive node. Thedrive and sense electrodes forming the capacitive node may come neareach other, but not make electrical contact with each other. Instead,the drive and sense electrodes may be capacitively coupled to each otheracross a space between them. A pulsed or alternating voltage applied tothe drive electrode (by touch-sensor controller 12) may induce a chargeon the sense electrode, and the amount of charge induced may besusceptible to external influence (such as a touch or the proximity ofan object). When an object touches or comes within proximity of thecapacitive node, a change in capacitance may occur at the capacitivenode and touch-sensor controller 12 may measure the change incapacitance. By measuring changes in capacitance throughout the array,touch-sensor controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include anarray of electrodes of a single type that may each form a capacitivenode. When an object touches or comes within proximity of the capacitivenode, a change in self-capacitance may occur at the capacitive node andcontroller 12 may measure the change in capacitance, for example, as achange in the amount of charge needed to raise the voltage at thecapacitive node by a pre-determined amount. As with a mutual-capacitanceimplementation, by measuring changes in capacitance throughout thearray, controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10. Thisdisclosure contemplates any suitable form of capacitive touch sensing,where appropriate.

In particular embodiments, one or more drive electrodes may togetherform a drive line running horizontally or vertically or in any suitableorientation. Similarly, one or more sense electrodes may together form asense line running horizontally or vertically or in any suitableorientation. In particular embodiments, drive lines may runsubstantially perpendicular to sense lines. Herein, reference to a driveline may encompass one or more drive electrodes making up the driveline, and vice versa, where appropriate. Similarly, reference to a senseline may encompass one or more sense electrodes making up the senseline, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in apattern on one side of a single substrate. In such a configuration, apair of drive and sense electrodes capacitively coupled to each otheracross a space between them may form a capacitive node. For aself-capacitance implementation, electrodes of only a single type may bedisposed in a pattern on a single substrate. In addition or as analternative to having drive and sense electrodes disposed in a patternon one side of a single substrate, touch sensor 10 may have driveelectrodes disposed in a pattern on one side of a substrate and senseelectrodes disposed in a pattern on another side of the substrate.Moreover, touch sensor 10 may have drive electrodes disposed in apattern on one side of one substrate and sense electrodes disposed in apattern on one side of another substrate. In such configurations, anintersection of a drive electrode and a sense electrode may form acapacitive node. Such an intersection may be a location where the driveelectrode and the sense electrode “cross” or come nearest each other intheir respective planes. The drive and sense electrodes do not makeelectrical contact with each other—instead they are capacitively coupledto each other across a dielectric at the intersection. Although thisdisclosure describes particular configurations of particular electrodesforming particular nodes, this disclosure contemplates any suitableconfiguration of any suitable electrodes forming any suitable nodes.Moreover, this disclosure contemplates any suitable electrodes disposedon any suitable number of any suitable substrates in any suitablepatterns.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 may indicate a touch or proximity input at the positionof the capacitive node. Touch-sensor controller 12 may detect andprocess the change in capacitance to determine the presence and locationof the touch or proximity input. Touch-sensor controller 12 may thencommunicate information about the touch or proximity input to one ormore other components (such one or more central processing units (CPUs))of a device that includes touch sensor 10 and touch-sensor controller12, which may respond to the touch or proximity input by initiating afunction of the device (or an application running on the device).Although this disclosure describes a particular touch-sensor controllerhaving particular functionality with respect to a particular device anda particular touch sensor, this disclosure contemplates any suitabletouch-sensor controller having any suitable functionality with respectto any suitable device and any suitable touch sensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices (PLDs) or programmable logic arrays (PLAs),application-specific ICs (ASICs). In particular embodiments,touch-sensor controller 12 comprises analog circuitry, digital logic,and digital non-volatile memory. In particular embodiments, touch-sensorcontroller 12 is disposed on a flexible printed circuit (FPC) bonded tothe substrate of touch sensor 10, as described below. The FPC may beactive or passive, where appropriate. In particular embodiments multipletouch-sensor controllers 12 are disposed on the FPC. Touch-sensorcontroller 12 may include a processor unit, a drive unit, a sense unit,and a storage unit. The drive unit may supply drive signals to the driveelectrodes of touch sensor 10. The sense unit may sense charge at thecapacitive nodes of touch sensor 10 and provide measurement signals tothe processor unit representing capacitances at the capacitive nodes.The processor unit may control the supply of drive signals to the driveelectrodes by the drive unit and process measurement signals from thesense unit to detect and process the presence and location of a touch orproximity input within the touch-sensitive area(s) of touch sensor 10.The processor unit may also track changes in the position of a touch orproximity input within the touch-sensitive area(s) of touch sensor 10.The storage unit may store programming for execution by the processorunit, including programming for controlling the drive unit to supplydrive signals to the drive electrodes, programming for processingmeasurement signals from the sense unit, and other suitable programming,where appropriate. Although this disclosure describes a particulartouch-sensor controller having a particular implementation withparticular components, this disclosure contemplates any suitabletouch-sensor controller having any suitable implementation with anysuitable components.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 may couple the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 may extend into or around (e.g.at the edges of) the touch-sensitive area(s) of touch sensor 10.Particular tracks 14 may provide drive connections for couplingtouch-sensor controller 12 to drive electrodes of touch sensor 10,through which the drive unit of touch-sensor controller 12 may supplydrive signals to the drive electrodes. Other tracks 14 may provide senseconnections for coupling touch-sensor controller 12 to sense electrodesof touch sensor 10, through which the sense unit of touch-sensorcontroller 12 may sense charge at the capacitive nodes of touch sensor10. Tracks 14 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, the conductivematerial of tracks 14 may be copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 may be silver or silver-based and have a width ofapproximately 100 μm or less. In particular embodiments, tracks 14 maybe made of ITO in whole or in part in addition or as an alternative tofine lines of metal or other conductive material. Although thisdisclosure describes particular tracks made of particular materials withparticular widths, this disclosure contemplates any suitable tracks madeof any suitable materials with any suitable widths. In addition totracks 14, touch sensor 10 may include one or more ground linesterminating at a ground connector (which may be a connection pad 16) atan edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of thesubstrate, outside the touch-sensitive area(s) of touch sensor 10. Asdescribed above, touch-sensor controller 12 may be on an FPC. Connectionpads 16 may be made of the same material as tracks 14 and may be bondedto the FPC using an anisotropic conductive film (ACF). Connection 18 mayinclude conductive lines on the FPC coupling touch-sensor controller 12to connection pads 16, in turn coupling touch-sensor controller 12 totracks 14 and to the drive or sense electrodes of touch sensor 10. Inanother embodiment, connection pads 16 may be connected to anelectro-mechanical connector (such as a zero insertion forcewire-to-board connector); in this embodiment, connection 18 may not needto include an FPC. This disclosure contemplates any suitable connection18 between touch-sensor controller 12 and touch sensor 10.

FIG. 2 illustrates an example exterior of an example active stylus 20.Active stylus 20 may include one or more components, such as buttons 30or sliders 32 and 34 integrated with an outer body 22. These externalcomponents may provide for interaction between active stylus 20 and auser or between a device and a user. As an example and not by way oflimitation, interactions may include communication between active stylus20 and a device, enabling or altering functionality of active stylus 20or a device, or providing feedback to or accepting input from one ormore users. The device may by any suitable device, such as, for exampleand without limitation, a desktop computer, laptop computer, tabletcomputer, personal digital assistant (PDA), smartphone, satellitenavigation device, portable media player, portable game console, kioskcomputer, point-of-sale device, or other suitable device. Although thisdisclosure provides specific examples of particular componentsconfigured to provide particular interactions, this disclosurecontemplates any suitable component configured to provide any suitableinteraction. Active stylus 20 may have any suitable dimensions withouter body 22 made of any suitable material or combination of materials,such as, for example and without limitation, plastic or metal. Inparticular embodiments, exterior components (e.g. 30 or 32) of activestylus 20 may interact with internal components or programming of activestylus 20 or may initiate one or more interactions with one or moredevices or other active styluses 20.

As described above, actuating one or more particular components mayinitiate an interaction between active stylus 20 and a user or betweenthe device and the user. Components of active stylus 20 may include oneor more buttons 30 or one or more sliders 32 and 34. As an example andnot by way of limitation, buttons 30 or sliders 32 and 34 may bemechanical or capacitive and may function as a roller, trackball, orwheel. As another example, one or more sliders 32 or 34 may function asa vertical slider 34 aligned along a longitudinal axis, while one ormore wheel sliders 32 may be aligned along the circumference of activestylus 20. In particular embodiments, capacitive sliders 32 and 34 orbuttons 30 may be implemented using one or more touch-sensitive areas.Touch-sensitive areas may have any suitable shape, dimensions, location,or be made from any suitable material. As an example and not by way oflimitation, sliders 32 and 34 or buttons 30 may be implemented usingareas of flexible mesh formed using lines of conductive material. Asanother example, sliders 32 and 34 or buttons 30 may be implementedusing a FPC.

Active stylus 20 may have one or more components configured to providefeedback to or accepting feedback from a user, such as, for example andwithout limitation, tactile, visual, or audio feedback. Active stylus 20may include one or more ridges or grooves 24 on its outer body 22.Ridges or grooves 24 may have any suitable dimensions, have any suitablespacing between ridges or grooves, or be located at any suitable area onouter body 22 of active stylus 20. As an example and not by way oflimitation, ridges 24 may enhance a user's grip on outer body 22 ofactive stylus 20 or provide tactile feedback to or accept tactile inputfrom a user. Active stylus 20 may include one or more audio components38 capable of transmitting and receiving audio signals. As an exampleand not by way of limitation, audio component 38 may contain amicrophone capable of recording or transmitting one or more users'voices. As another example, audio component 38 may provide an auditoryindication of a power status of active stylus 20. Active stylus 20 mayinclude one or more visual feedback components 36, such as alight-emitting diode (LED) indicator. As an example and not by way oflimitation, visual feedback component 36 may indicate a power status ofactive stylus 20 to the user.

One or more modified surface areas 40 may form one or more components onouter body 22 of active stylus 20. Properties of modified surface areas40 may be different than properties of the remaining surface of outerbody 22. As an example and not by way of limitation, modified surfacearea 40 may be modified to have a different texture, temperature, orelectromagnetic characteristic relative to the surface properties of theremainder of outer body 22. Modified surface area 40 may be capable ofdynamically altering its properties, for example by using hapticinterfaces or rendering techniques. A user may interact with modifiedsurface area 40 to provide any suitable functionally. For example andnot by way of limitation, dragging a finger across modified surface area40 may initiate an interaction, such as data transfer, between activestylus 20 and a device.

One or more components of active stylus 20 may be configured tocommunicate data between active stylus 20 and the device. For example,active stylus 20 may include one or more tips 26 or nibs. Tip 26 mayinclude one or more electrodes configured to communicate data betweenactive stylus 20 and one or more devices or other active styluses. Tip26 may be made of any suitable material, such as a conductive material,and have any suitable dimensions, such as, for example, a diameter of 1mm or less at its terminal end. Active stylus 20 may include one or moreports 28 located at any suitable location on outer body 22 of activestylus 20. Port 28 may be configured to transfer signals or informationbetween active stylus 20 and one or more devices or power sources. Port28 may transfer signals or information by any suitable technology, suchas, for example, by universal serial bus (USB) or Ethernet connections.Although this disclosure describes and illustrates a particularconfiguration of particular components with particular locations,dimensions, composition and functionality, this disclosure contemplatesany suitable configuration of suitable components with any suitablelocations, dimensions, composition, and functionality with respect toactive stylus 20.

FIG. 3 illustrates an example internal components of example activestylus 20. Active stylus 20 may include one or more internal components,such as a controller 50, sensors 42, memory 44, or power source 48. Inparticular embodiments, one or more internal components may beconfigured to provide for interaction between active stylus 20 and auser or between a device and a user. In other particular embodiments,one or more internal components, in conjunction with one or moreexternal components described above, may be configured to provideinteraction between active stylus 20 and a user or between a device anda user. As an example and not by way of limitation, interactions mayinclude communication between active stylus 20 and a device, enabling oraltering functionality of active stylus 20 or a device, or providingfeedback to or accepting input from one or more users.

Controller 50 may be a microcontroller or any other type of processorsuitable for controlling the operation of active stylus 20. Controller50 may be one or more ICs—such as, for example, general-purposemicroprocessors, microcontrollers, PLDs, PLAs, or ASICs. Controller 50may include a processor unit, a drive unit, a sense unit, and a storageunit. The drive unit may supply signals to electrodes of tip 26 throughcenter shaft 41. The drive unit may also supply signals to control ordrive sensors 42 or one or more external components of active stylus 20.The sense unit may sense signals received by electrodes of tip 26through center shaft 41 and provide measurement signals to the processorunit representing input from a device. The sense unit may also sensesignals generated by sensors 42 or one or more external components andprovide measurement signals to the processor unit representing inputfrom a user. The processor unit may control the supply of signals to theelectrodes of tip 26 and process measurement signals from the sense unitto detect and process input from the device. The processor unit may alsoprocess measurement signals from sensors 42 or one or more externalcomponents. The storage unit may store programming for execution by theprocessor unit, including programming for controlling the drive unit tosupply signals to the electrodes of tip 26, programming for processingmeasurement signals from the sense unit corresponding to input from thedevice, programming for processing measurement signals from sensors 42or external components to initiate a pre-determined function or gestureto be performed by active stylus 20 or the device, and other suitableprogramming, where appropriate. As an example and not by way oflimitation, programming executed by controller 50 may electronicallyfilter signals received from the sense unit. Although this disclosuredescribes a particular controller 50 having a particular implementationwith particular components, this disclosure contemplates any suitablecontroller having any suitable implementation with any suitablecomponents.

In particular embodiments, active stylus 20 may include one or moresensors 42, such as touch sensors, gyroscopes, accelerometers, contactsensors, or any other type of sensor that detect or measure data aboutthe environment in which active stylus 20 operates. Sensors 42 maydetect and measure one or more characteristic of active stylus 20, suchas acceleration or movement, orientation, contact, pressure on outerbody 22, force on tip 26, vibration, or any other suitablecharacteristic of active stylus 20. As an example and not by way oflimitation, sensors 42 may be implemented mechanically, electronically,or capacitively. As described above, data detected or measured bysensors 42 communicated to controller 50 may initiate a pre-determinedfunction or gesture to be performed by active stylus 20 or the device.In particular embodiments, data detected or received by sensors 42 maybe stored in memory 44. Memory 44 may be any form of memory suitable forstoring data in active stylus 20. In other particular embodiments,controller 50 may access data stored in memory 44. As an example and notby way of limitation, memory 44 may store programming for execution bythe processor unit of controller 50. As another example, data measuredby sensors 42 may be processed by controller 50 and stored in memory 44.

Power source 48 may be any type of stored-energy source, includingelectrical or chemical-energy sources, suitable for powering theoperation of active stylus 20. In particular embodiments, power source48 may be charged by energy from a user or device. As an example and notby way of limitation, power source 48 may be a rechargeable battery thatmay be charged by motion induced on active stylus 20. In otherparticular embodiments, power source 48 of active stylus 20 may providepower to or receive power from the device. As an example and not by wayof limitation, power may be inductively transferred between power source48 and a power source of the device.

FIG. 4 illustrates an example active stylus 20 with an example device52. Device 52 may have a display (not shown) and a touch sensor with atouch-sensitive area 54. Device 52 display may be a liquid crystaldisplay (LCD), a LED display, a LED-backlight LCD, or other suitabledisplay and may be visible though a cover panel and substrate (and thedrive and sense electrodes of the touch sensor disposed on it) of device52. Although this disclosure describes a particular device display andparticular display types, this disclosure contemplates any suitabledevice display and any suitable display types.

Device 52 electronics may provide the functionality of device 52. Asexample and not by way of limitation, device 52 electronics may includecircuitry or other electronics for wireless communication to or fromdevice 52, execute programming on device 52, generating graphical orother user interfaces (UIs) for device 52 display to display to a user,managing power to device 52 from a battery or other power source, takingstill pictures, recording video, other suitable functionality, or anysuitable combination of these. Although this disclosure describesparticular device electronics providing particular functionality of aparticular device, this disclosure contemplates any suitable deviceelectronics providing any suitable functionality of any suitable device.

In particular embodiments, active stylus 20 and device 52 may besynchronized prior to communication of data between active stylus 20 anddevice 52. As an example and not by way of limitation, active stylus 20may be synchronized to device through a pre-determined bit sequencetransmitted by the touch sensor of device 52. As another example, activestylus 20 may be synchronized to device by processing the drive signaltransmitted by drive electrodes of the touch sensor of device 52. Activestylus 20 may interact or communicate with device 52 when active stylus20 is brought in contact with or in proximity to touch-sensitive area 54of the touch sensor of device 52. In particular embodiments, interactionbetween active stylus 20 and device 52 may be capacitive or inductive.As an example and not by way of limitation, when active stylus 20 isbrought in contact with or in the proximity of touch-sensitive area 54of device 52, signals generated by active stylus 20 may influencecapacitive nodes of touch-sensitive area of device 52 or vice versa. Asanother example, a power source of active stylus 20 may be inductivelycharged through the touch sensor of device 52, or vice versa. Althoughthis disclosure describes particular interactions and communicationsbetween active stylus 20 and device 52, this disclosure contemplates anysuitable interactions and communications through any suitable means,such as mechanical forces, current, voltage, or electromagnetic fields.

In particular embodiments, measurement signal from the sensors of activestylus 20 may initiate, provide for, or terminate interactions betweenactive stylus 20 and one or more devices 52 or one or more users, asdescribed above. Interaction between active stylus 20 and device 52 mayoccur when active stylus 20 is contacting or in proximity to device 52.As an example and not by way of limitation, a user may perform a gestureor sequence of gestures, such as shaking or inverting active stylus 20,whilst active stylus 20 is hovering above touch-sensitive area 54 ofdevice 52. Active stylus may interact with device 52 based on thegesture performed with active stylus 20 to initiate a pre-determinedfunction, such as authenticating a user associated with active stylus 20or device 52. Although this disclosure describes particular movementsproviding particular types of interactions between active stylus 20 anddevice 52, this disclosure contemplates any suitable movementinfluencing any suitable interaction in any suitable way.

FIG. 5 illustrates example power management systems and power sourcesfor a touch sensor system. Power management systems and power sourcesmay be associated with components of the touch-sensor system, such asactive styluses, touch-sensitive devices, and the components associatedwith active styluses and touch-sensitive devices. Active stylus 20 mayhave one or more power sources 48. Likewise, touch-sensitive device 52may have one or more power sources 58. Power sources 48 and 58 maycommunicate with controllers 50 and 12, respectively. In particularembodiments, the communication is controlled or monitored by one or moregraphical user interfaces operating on any suitable active stylus ordevice. Power sources 48 and 58 may store, receive, transmit, or produceelectric energy suitable for use by a touch sensor system or associatedcomponents. In particular embodiments, electric energy is received ortransmitted by any suitable method such as wiring, direct physicalcontact, temperature gradients, piezoelectric materials, mechanicalmethods, electromagnetic radiation, or any suitable combination thereof.Power sources 48 and 58 may include any suitable component thatdelivers, receives, produces, or modifies energy, such as a transformer.Power sources 48 and 58 may convert any kind of electric energy stored,produced, received, or transmitted to any other kind of electric energysuitable for use by a touch sensor system and its associated components.Electric energy may be in any suitable form, such as electric fields,magnetic fields, static configurations of electric charge, and electriccurrents.

Power source 48 may be external or internal to active stylus 20, andpower source 58 may be external or internal to touch-sensitive device52. In particular embodiments, an internal power source is a battery ora capacitor. In particular embodiments, an external power source is awall outlet or another device, such as a computer. A power sourceinternal to one active stylus or device may be external to anotheractive stylus or device. As an example of a particular embodiment, powersource 58 is internal to touch-sensitive device 52, while also servingas an external power source 48 for active stylus 20. While thisdisclosure describes specific examples of particular embodiments ofpower sources 48 and 58, this disclosure contemplates any suitable powersources 48 and 58 delivering, receiving, storing or producing anysuitable kind of electric energy by any suitable method to or from anysuitable sources or destinations.

Active stylus 20 may have one or more power management systems 60.Likewise, touch-sensitive device 52 may have one or more powermanagement systems 56. Power management systems 60 and 56 maycommunicate with controllers 50 and 12, respectively. In particularembodiments, the communication is controlled or monitored by a graphicaluser interface operating on an active stylus or device. Power managementsystems 60 and 56 may control, modify, or record the receipt,production, or transfer of electric energy suitable for use by a touchsensor system or its associated components. In particular embodiments,power management systems 60 and 56 allocate to one or more componentsassociated with a touch sensor system electric energy existing on orincoming to one or more components associated with the touch sensorsystem. In particular embodiments, power management systems 60 and 56use criteria, such as metrics, to initiate, allocate, and terminate theallocation of energy between one or more components of a touch sensorsystem. In particular embodiments, power management systems 60 and 56allocate a particular amount of power to one or more componentsassociated with a touch sensor system, and are capable of allocatingdifferent amounts of power to particular components at different times.As an example, a power management system 60 determines power modes of anactive stylus. A power mode describes the amount of power sent to one ormore components associated with an active stylus. The power managementsystem 60 may transition the active stylus between power modes based atleast in part on input from a user or an active stylus or device. Agraphical user interface may allow a user to control or monitor thepower modes of an active stylus and the method or criteria used totransition between them.

In particular embodiments, an active stylus may harvest energy from theactive stylus's environment. An active stylus may harvest any suitabletype of energy, such as kinetic, acoustic, thermal, solar, or electricenergy. Energy harvested by an active stylus may be converted to andstored in any suitable form of electric energy, such as electricalcurrents and distributions of charge. The electric energy may be used topower the active stylus or its components.

FIG. 6 illustrates an example active stylus with kinetic energyharvesters. Kinetic energy is harvested by one or more kineticharvesters 62 on or in active stylus 20. In particular embodiments,kinetic harvester 62 includes a spring. In particular embodiments,kinetic harvester 62 is a piezoelectric element in an active stylus. Inparticular embodiments, kinetic harvester 62 is a magnet and a conductorformed into one or more loops. Motion of active stylus 20 moves themagnet relative to the conductor, converting kinetic energy intoelectric energy. In particular embodiments, kinetic harvester 62 is avibration-dependent capacitor that has some initial charge on it.Movement of the active stylus changes the distance between chargedsurfaces of the capacitor, converting kinetic energy into electricalcurrents. In particular embodiments, kinetic harvester 62 is a fluid ina closed volume, such as a pressurized hydraulic fluid, coupled with oneor more piezoelectric elements. Movement of the active stylus changespressure points in the fluid, driving one or more pistons. Movement ofthe pistons is converted into electric energy by the piezoelectricelements.

Kinetic energy may be converted into electric energy when an activestylus 20 experiences mechanical forces. For example, kinetic energy maybe converted when the active stylus undergoes lateral acceleration,rotation, or vibration. In particular embodiments, kinetic energy isharvested by kinetic harvester 62 when active stylus 20 is shaken. Inparticular embodiments, kinetic energy is harvested by kinetic harvester62 when active stylus 20 moves during operation, such as writing on atouch-sensitive display. In particular embodiments, kinetic energy isharvested by kinetic harvester 62 when active stylus 20 moves while notin operation, for example when active stylus 20 is stored in a pocket,attached to a touch-sensitive device, or moved by a user. In particularembodiments, kinetic energy is harvested by kinetic harvester 62 whenkinetic harvester 62 vibrates, for example due to incoming acousticwaves. While this disclosure describes specific examples of particularembodiments of kinetic energy harvesters and the kinetic energyharvested, this disclosure contemplates any suitable kinetic harvesterslocated in any suitable location harvesting any suitable kinetic energy.

FIG. 7 illustrates an example active stylus with thermal energyharvesters. Thermal energy is harvested by one or more thermalharvesters 64 on or in active stylus 20. In particular embodiments,thermal harvester is any suitable pyroelectric material. In particularembodiments, thermal harvester 64 is a thermal electric generator. Forexample, a temperature gradient at the junction 70 of first conductingmaterial 66 and second conducting material 68 converts thermal energyinto electric energy. As an example of a particular embodiment, firstconducting material 66 covers or is part of any suitable portion of theouter body 22 of active stylus 20. Second conducting material 68 coversor is part of another portion of the outer body 22 of active stylus 20or is located within the body of active stylus 20, and has a junction 70with first conducting material 66. As an example, first conductingmaterial 66 and second conducting material 68 are arranged in concentriccylinders 72, with first conducting material 66 on or part of the outerbody 22 of active stylus 20. In particular embodiments, the temperaturegradient is based on the difference in temperature between the activestylus's external environment, such as the temperature of a user or theambient temperature, and the active stylus's internal environment. Inparticular embodiments, the temperature gradient is based on exposingdifferent portions of the active stylus's outer surface to differenttemperatures, such as a user's temperature and the ambient temperatureof the active stylus's external environment. While this disclosuredescribes specific examples of particular embodiments of thermal energyharvesters and the thermal energy harvested, this disclosurecontemplates any suitable thermal harvesters located in any suitablelocation harvesting any suitable thermal energy.

FIG. 8 illustrates an example active stylus with electric energyharvesters. Electric energy is harvested by one or more electric energyharvesters 74 on or in active stylus 20. In particular embodiments,electric energy harvester 74 is an antenna, such as one or more coils ofconducting material, located in or on active stylus 20. The antennaharvests electric energy in a suitable frequency range, such as therange used in radio frequency identification. As an example, theelectric energy may be produced by a device associated with an activestylus, such as a touch-sensitive device. In particular embodiments,electric energy harvester 74 is an induction coil located in activestylus 20. The induction coil receives electric energy, for exampleelectric energy produced by a touch-sensitive device. While thisdisclosure describes specific examples of particular embodiments ofelectric energy harvesters and the electric energy harvested, thisdisclosure contemplates any suitable electric energy harvesters locatedin any suitable location harvesting any suitable electric energy.

FIG. 9 illustrates an example active stylus with solar energyharvesters. Solar energy is harvested by one or more solar energyharvesters 76 on or in active stylus 20. In particular embodiments,solar energy harvester 76 is a photovoltaic, such as a solar panel, madeof suitable material such as cadmium telluride. Solar energy of asuitable wavelength for the photovoltaic material used is harvested byactive stylus 20. The photovoltaic material may have any suitabledimensions located on any suitable area of active stylus 20. While thisdisclosure describes specific examples of particular embodiments ofsolar energy harvesters, this disclosure contemplates any suitable solarenergy harvesters located in any suitable location on the active stylusharvesting any suitable wavelength of solar energy.

Herein, reference to a computer-readable non-transitory storage mediumencompasses a semiconductor-based or other integrated circuit (IC)(such, as for example, a field-programmable gate array (FPGA) or anapplication-specific IC (ASIC)), a hard disk, an HDD, a hybrid harddrive (HHD), an optical disc, an optical disc drive (ODD), amagneto-optical disc, a magneto-optical drive, a floppy disk, a floppydisk drive (FDD), magnetic tape, a holographic storage medium, asolid-state drive (SSD), a RAM-drive, a SECURE DIGITAL card, a SECUREDIGITAL drive, or another suitable computer-readable non-transitorystorage medium or a combination of two or more of these, whereappropriate. A computer-readable non-transitory storage medium may bevolatile, non-volatile, or a combination of volatile and non-volatile,where appropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Moreover,reference in the appended claims to an apparatus or system or acomponent of an apparatus or system being adapted to, arranged to,capable of, configured to, enabled to, operable to, or operative toperform a particular function encompasses that apparatus, system,component, whether or not it or that particular function is activated,turned on, or unlocked, as long as that apparatus, system, or componentis so adapted, arranged, capable, configured, enabled, operable, oroperative.

What is claimed is:
 1. A stylus comprising: one or more electrodes andone or more computer-readable non-transitory storage media embodyinglogic for transmitting signals wirelessly from the stylus to a devicethrough a touch sensor of the device; and one or more sensors harvestingkinetic, thermal, solar, or electric energy from the stylus or anenvironment of the stylus.
 2. The stylus of claim 1, wherein the kineticenergy is harvested by one or more of: a piezoelectric element; a magnetinductively coupled to a conductor; a fluid in a closed volume; avariable capacitor; or a spring.
 3. The stylus of claim 1, wherein thethermal energy is harvested by a temperature difference between thestylus's external environment and a user or the stylus's internalenvironment.
 4. The stylus of claim 1, wherein the thermal energy isharvested by a temperature difference between a first conductorcomprising at least a portion of the outer body of the stylus and asecond conductor comprising another portion of the outer body of thestylus.
 5. The stylus of claim 1, wherein the thermal energy isharvested by a temperature difference between a first conductorcomprising at least a portion of the outer body of the stylus and asecond conductor located in the interior of the stylus.
 6. The stylus ofclaim 1, wherein the electric energy is harvested by one or moreantennas or induction coils.
 7. The stylus of claim 1, wherein theelectric energy is produced by a touch-sensitive device.
 8. The stylusof claim 1, wherein the solar energy is harvested by a photovoltaicmaterial on or near the surface of the stylus.
 9. An method comprising:harvesting, by one or more sensors on or in a stylus, kinetic, thermal,solar, or electric energy of the stylus or from an environment of thestylus, the stylus comprising one or more electrodes and one or morecomputer-readable non-transitory storage media embodying logic fortransmitting signals wirelessly from the stylus to a device through atouch sensor of the device.
 10. The method of claim 9, wherein thekinetic energy is harvested by: a piezoelectric element; a magnetinductively coupled to a conductor; a fluid in a closed volume; avariable capacitor; or a spring.
 11. The method of claim 9, wherein thethermal energy is harvested by a temperature difference between thestylus's external environment and a user or the stylus's internalenvironment.
 12. The method of claim 9, wherein the thermal energy isharvested by a temperature difference between a first conductorcomprising at least a portion of the outer body of the stylus and asecond conductor comprising another portion of the outer body of thestylus.
 13. The method of claim 9, wherein the thermal energy isharvested by a temperature difference between a first conductorcomprising at least a portion of the outer body of the stylus and asecond conductor located in the interior of the stylus.
 14. The methodof claim 9, wherein the electric energy is harvested by one or moreantennas or induction coils.
 15. The method of claim 9, wherein theelectric energy is produced by a touch-sensitive device.
 16. The methodof claim 9, wherein the solar energy is harvested by a photovoltaicmaterial on or near the surface of the stylus.
 17. One or morecomputer-readable non-transitory storage media embodying logic that isoperable when executed to: harvest, by one or more sensors on or in astylus, kinetic, thermal, solar, or electric energy of the stylus orfrom an environment of the stylus, the stylus comprising one or moreelectrodes and the media further embodying logic for transmittingsignals wirelessly to a device through a touch sensor of the device. 18.The media of claim 17, wherein the kinetic energy is harvested by: apiezoelectric element; a magnet inductively coupled to a conductor; afluid in a closed volume; a variable capacitor; or a spring.
 19. Themedia of claim 17, wherein the thermal energy is harvested by atemperature difference between the stylus's external environment and auser or the stylus's internal environment.
 20. The media of claim 17,wherein the electric energy is harvested by one or more antennas orinduction coils.